A prospective study on the efficacy of sequential treatment of technology Lipido‐Colloid Impregnated with Silver and Technology Lipido‐Colloid Nano‐Oligosaccharide Factor in the management of venous leg ulcers

Abstract Background and Aims Venous leg ulcers (VLUs) are associated with significant morbidity and poor quality of life (QOL). Compression therapy and wound dressing are the mainstay treatment options. Technology Lipido‐Colloid Impregnated with Silver (TLC‐Ag) reduces bacterial load and Technology Lipido‐Colloid Nano‐Oligosaccharide Factor (TLC‐NOSF) reduces elevated matrix metalloproteinases and improve wound healing. However, evidence is scarce on the role of sequential therapy. This study aims to evaluate if sequential treatment with TLC‐Ag and TLC‐NOSF improves VLU wound healing and QOL. Methods This is a prospective cohort study from May 2020 to October 2021 on patients with VLUs who received sequential therapy, consisting of 2 weeks of TLC‐Ag followed by two‐layer compression bandage (2LB) with TLC‐NOSF until complete wound healing. Participants were followed‐up with weekly dressing changes. Our primary outcomes were wound area reduction (WAR) and Pressure Ulcer Scale of Healing (PUSH) score. Our secondary outcomes were QOL measures. Results There were 28 patients with 57.1% males (n = 16) with a mean age of 65.3 years. Mean duration of VLU was 13.9 ± 11.7 weeks before the initiation of sequential therapy. Mean baseline wound area was 8.44 cm2. Median time to wound healing was 10 weeks. 57.1% of patients achieved complete wound closure at 3 months. There was significant WAR after 1 month (mean area 8.44–5.81 cm2, 31.2% decrease) and after 3 months (mean area 8.44–2.53 cm2, 70.0% decrease). Mean monthly WAR was 28.9%. PUSH score also decreased at 1 month (16.5% decrease, p < 0.001) and 3 months (63.3% decrease, p < 0.001) marks following the sequential therapy. EuroQol Visual Analog Scale (EQ‐VAS) improved following sequential therapy (baseline: 69.0 ± 15.0, week 13: 80.2 ± 13.2, p < 0.001). Conclusion Sequential therapy with TLC‐Ag followed by TLC‐NOSF and 2LB is feasible, with good wound healing and improvement in QOL of patients with VLUs.


| INTRODUCTION
Chronic venous insufficiency (CVI) is a chronic and debilitating disease with a prevalence of 25%-40% in females and 10%-20% in males. 1,2 Severe CVI may be complicated by venous leg ulcers (VLUs) or malignant transformation into Marjolin's ulcer. 3,4 VLUs are the most common type of chronic ulcers occurring in the lower extremities, prevalent in 1% of the global population. 5 VLUs are associated with high chronicity, rates of recurrence, and poor quality of life (QOL). Chronic nonhealing wounds also predispose to secondary infections and further complications, resulting in higher morbidity. 6 These inadvertent complications of VLUs, therefore result in significant socioeconomic burden 7 ; locally in Singapore, 1-year VLU recurrence was 52.5% with median interval of 9.5 months between healing and recurrence, with an estimated cost of US dollar (USD) 16,761 per patient. 7 Current literature and standard clinical practice recommends a multimodal approach for the treatment of VLUs, involving compression therapy and wound care. 8 Compression therapy has been shown to result in 60%-70% complete ulcer healing after 12-24 weeks of use. 9 Another facet of management of VLU involves wound care, which consists of wound assessment, monitoring, and dressings. 10 Recent evidence has shown that a two-layer compression bandage (2LB) has similar time to healing compared to a four-layer compression bandage (4LB), but with better cost-effectiveness and associated with greater patient compliance. 11,12 Use of Technology Lipido-Colloid with silver dressing (TLC-Ag) has been shown to reduce bacterial load and wound area reduction (WAR). 13 Technology Lipido-Colloid Nano-Oligosaccharide Factor (TLC-NOSF) has also been shown to reduce the inflammatory cascade and improve WAR in VLUs. 14,15 A small noncomparative study on 36 patients showed use of UrgoTul ® (Laboratoires URGO) and K-Four ® (Laboratoires URGO, Paris, France) showed that 50% of patients had healed VLU in 46.8 days following treatment and reported reduced pain at dressing change. 16 However, there is a paucity of evidence on combination of compression therapy and wound dressing on VLU outcomes. A review in 2013 identified that while patients undergo sequential treatments, that is, application of different dressings over time, there is no evidence on the order or duration of each therapy. 17 Clinical practice guidelines by the Society for Vascular Surgery similarly did not make any recommendations on the above. 8 Hence, we propose a sequential protocol consisting of initial TLC-Ag followed by combination of TLC-NOSF with 2LB. Our aim is to evaluate the efficacy of this sequential protocol on healing of VLUs and QOL of patients.

| MATERIALS AND METHODS
This is a noncomparative prospective single-center study conducted at a 1300-bed university-affiliated tertiary hospital in Singapore. This is a 13-week study ( Figure 1) with a recruitment period from May 2020 to October 2021, and a study period from August 2020 to December 2021. Patients were recruited at Week 0, with treatment commenced at Week 1 and follow-up completed at Week 13. The 12-week follow-up timeframe was adopted as compression therapy has been shown to result in 60%-70% complete ulcer healing after 12-24 weeks of use. 9 Inclusion criteria were patients ≥21 years old, a VLU surface area between 2 and 50 cm 2 lasting 1-12 months before recruitment and a normal ankle circumference and ankle-brachial pressure index (ABPI). For patients with multiple ulcers, only one

Key points
• Technology Lipido-Colloid Impregnated with Silver (TLC-Ag) and Technology Lipido-Colloid Nano-Oligosaccharide Factor (TLC-NOSF) have been shown to reduce bacterial load and improve wound healing. However, evidence is scarce on the use of sequential therapy with various wound dressings and compression therapy for patients with venous leg ulcers (VLUs).
• Our study aims to evaluate the efficacy and safety of a novel sequential therapy with 2 weeks of TLC-Ag followed by TLC-NOSF with two-layer compression bandage for patients with VLUs.
• There was significant 1-month (31.2%) and 3-month (70.0%) wound area reduction with majority obtaining complete wound closure (57.1%) at 3 months. There was also significant improvement in quality of life quantified by the EuroQol Visual Analog Scale. target ulcer which best met the selection criteria was chosen for evaluation. The other ulcers were treated with standard treatment procedures, which usually include silver-based foam dressing together with compression therapy. Exclusion criteria were non-VLUs or patients planned for venous surgery within the study period.
The complete list of inclusion and exclusion criteria are outlined in

| Study protocol
All patients of our wound care specialist outpatient clinic (SOC) were screened for eligibility for the study by our on-site principal investigator or dedicated wound nurse according to the inclusion and exclusion criteria. Patients who had received prior local treatment for VLUs were not excluded from the selection process.
Eligible participants were briefed at a dedicated consultation room and opportunities were given to ask on the details of the study. An on-site translator was available for non-English participants. Informed consent was taken from each participant who agreed to enroll into the study. Patients that completed the study protocol were remunerated at the end of the study for their participation.
The study protocol is illustrated in Figure 1. Baseline patient and wound characteristics were collected from all participants at the start of the study. Each consultation subsequently was conducted at our wound care SOC. Following data collection, the VLUs were cleansed with normal saline solution. VLUs of enrolled subjects were dressed with UrgoClean Ag ® (TLC-Ag) (Laboratoires URGO) for 2 weeks, followed by 11 weeks of a combination of UrgoK2 ® or UrgoK2 Lite ® (2LB) (Laboratoires URGO) together with UrgoStart ® (TLC-NOSF) (Laboratoires URGO). Neutral absorbent dressings were used for excess exudate management. Frequency of dressing and bandage changes was standardized to once per week but subject to clinical judgment. Use of additional local treatment such as local antiseptic pastes, zinc pastes, or corticosteroids were F I G U R E 1 Study protocol outlining the timeline from recruitment to completion of study.
T A B L E 1 Inclusion and exclusion criteria used in our study.

Inclusion criteria
Exclusion criteria

| Study variables and outcomes
Baseline demographics including age, gender, comorbidities, and ulcer characteristics were recorded. Ulcer assessment included the Falanga wound bed score and Pressure Ulcer Scale of Healing (PUSH) score. 19 The PUSH score is an easy-to-use scoring system which permits monitoring of global healing results in wound management due to its comprehensive description of wound exudate, size, and tissue type. While it was initially designed for characterizing pressure ulcers, its use has since been validated to be effective in the grading of VLUs. 20,21 The EuroQol 5-dimensional 5-level (EQ-5D-5L) 22 was administered to each participant during the first (on Week 0) and last visit (on Week 13). Its use has been validated in monitoring the healing process of VLUs and discriminating between healed and nonhealed VLUs. 23 The EQ-5D-5L consists of five domains: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression. Each domain is graded using a 5-point Likert scale. 1 corresponds to no complications, and 5 corresponds to severe complications. Participants are represented by a five-digit health state, 11111 being the best health state to 55555 being the worst, with a total of 3125 possible health states. From each health state, a single index utility score can be calculated using country-specific value sets. For the purpose of this study, the crosswalk US value sets were used as a value set for Singapore has yet to be published on the EuroQol database. 22 The questionnaire also includes a visual analog scale (EQ-VAS) as a global rating of selfperceived health, which has a maximum score of 100 indicating "the best health you can imagine." Our primary outcomes were incidence of complete wound closure, WAR and PUSH score. A healed VLU was defined as complete wound closure. Our secondary outcomes were health-related QOL measures, that is, incidence of perfect health state (11111) measured using the EQ-5D-5L, utility score (calculated using the country-specific value sets), and EQ-VAS score.

| Statistical analysis
All statistical analyses were performed using Jamovi Version 2.3.18 (Jamovi). 24 Categorical variables were expressed as n (%), and continuous variables were described as mean ± standard deviation (SD) unless otherwise specified. Two-sided paired samples t test was used to compare VLU wound size and QOL outcomes before and after implementation of the treatment protocol. Statistical significance was defined with an a priori level of significance set as p < 0.05.
Kaplan-Meier analysis was used to analyze the cumulative time to wound healing.

| Patient demographics
Patient demographics are detailed in left-sided (n = 15/28). The mean duration of the VLUs was 13.9 ± 11.65 weeks before the sequential treatment. The mean PUSH score was 11.0 ± 2.25 with a lowest score of 7 and a highest score of 15 at the start of the study (Table 3).

| Primary outcomes
Cumulative wound healing is illustrated in Figure 2

| DISCUSSION
The use of compression therapy has been validated and is recommended as mainstay therapy in treating VLUs. 8,9 However, evidence on the use of sequential therapy of different wound dressings in combination with compression therapy is scarce. Our study demonstrates the feasibility and efficacy of a sequential treatment protocol with 2 weeks of TLC-Ag, followed by an 11-week combination of TLC-NOSF and 2LB.
In present guidelines, silver-containing dressings, such as TLC-  13 Heavily colonized wounds were defined as the presence of ≥3 of the following: pain between dressing changes, perilesional skin erythema, edema, foul odor, and heavy exudation. 13 Translational study on the use of nanocrystalline silver dressing in VLU also showed significant reduction in bacterial count after 12 weeks (p = 0.01) and demonstrated that heavy neutrophil infiltration is associated with delayed wound healing. 25 Hence, our study adopted the use of TLC-Ag during the first 2 weeks of the treatment protocol as a bridging regimen to reduce bacterial load and promote wound healing for subsequent sequential therapy with combination 2LB and TLC-NOSF. Compliance and tolerance to treatment is another important consideration in the management of chronic wound. While recent evidence showed that 2LB has similar healing outcomes compared to 4LB, 11,12 other advantages of 2LB over 4LB have been described.
2LB has been reported to be more tolerable as it is less bulky. 11,12 To add on, pain has been reported to be the most important factor impairing the QOL in patients with VLU. 34,35 A multicenter RCT of 187 patients comparing 2-4LB reported more significant reduction in pain over time between dressing changes when 2LB was used compared to 4LB, although this did not reach statistical significance. 36 Our study is unable to validate this study as this is a singlearm study assessing the efficacy and safety of pilot sequential T A B L E 4 1-and 3-month outcomes after the treatment protocol.  therapy. However, we did demonstrate significant reduction in pain and discomfort after the sequential therapy (score 2.25 ± 0.78 vs. Impairment of QOL is a significant complication of VLUs. 6 Hence, we included health-related QOL measures as our secondary outcomes, that is, the incidence of perfect health state (11,111) measured using the EQ-5D-5L, utility score (calculated using the US value sets), and EQ-VAS score. The EQ-5D-5L has been validated to discriminate between healed and nonhealed VLUs (healed: mean 0.89, nonhealed: mean 0.73, effect size 0.76 [medium]). 23 Our study similarly showed higher utility scores in healed VLUs (healed: 0.870 ± 0.169 vs. nonhealed: 0.812 ± 0.189, p = 0.39). This likely did not reach statistical significance due to our small sample size.
Nevertheless, we showed improvement in QOL in patients with healed VLU, as represented by increase in incidence of perfect health states, EQ-VAS score, and utility score.
Our study has its strengths. It is a prospective study with welldefined inclusion and exclusion criteria and study protocol. We also included multiple outcome measures ranging from WAR to QOL measures. Our study showed comparable outcomes with individual studies reporting on the efficacy of TLC-NOSF (compared to neutral TLC), 14 and TLC-Ag (compared to neutral TLC). 13 To our knowledge, this is also the first study that reported sequential therapy with TLC-Ag for the initial reduction of bacterial load, followed by combination of 2LB with TLC-NOSF. Our study is limited by a small sample size of 28 which may not be representative of the VLU population locally; however, a sample size of 12 has been determined to be adequate for

| CONCLUSION
This prospective study demonstrated that sequential therapy for VLUs with 2 weeks of TLC-Ag followed by TLC-NOSF and 2LB is feasible and efficacious with good wound healing and QOL improvement in our cohort. This study should serve as a precedence for future large multi-center well-designed RCTs to determine the effectiveness and long-term outcomes of sequential therapy compared to other treatment options such as TLC-Ag alone or 2LB alone. writing-review and editing. All authors have read and approved the final version of the manuscript.